Combustion properties of MgO for UVA emission

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2017-08

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Abstract

The goal of this study is to formulate a pyrotechnic mixture that emits strongly in the ultraviolet (specifically, UVA) spectrum (i.e., 315-400 nm). This goal was accomplished by testing several formulations using a UV-VIS spectrometer to examine emission spectra upon combustion. The candidate formulations used either aluminum or magnesium powders as the fuel material and were combined with several different solid oxidizers to synthesize a total of 17 candidate formulations. Results showed that the high temperature emission of magnesium oxide was the key ingredient for enhancing UVA emission. Thermal equilibrium chemical modeling using REAL code software shows that the flame temperature needs to be greater than 2369 K for MgO emission to be achieved. Also, UVA emission was shown to be a strong function of stoichiometry. For example, the formulation including Mg/KClO4 produces significant MgO at elevated temperatures to emit well in the UVA. As this mixture becomes increasingly fuel rich, emission intensity is optimized. The additional Mg from the fuel rich mixture combines with oxygen from air to produce greater concentration of MgO that optimize the overall emission intensity. This study provides a foundational understanding on how to use a thermite reaction properties such as adiabatic flame temperature at stoichiometry to engineer a specific response, in this case heightened UVA emission.

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Keywords

MgO, UVA emission

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